Methods for producing oil and/or gas

ABSTRACT

A method for producing oil from an underground formation comprising providing a first well in one or more formations, the first well comprising a plurality of sections along a length of the well; providing a second well in the formation; injecting an enhanced oil recovery formulation into at least a first section and a second section of the first well and into the formation; flowing the formulation and/or oil towards the second well in one or more formations; producing the formulation and/or oil from the second well; and then modifying the injecting into the second section, while continuing the injecting into the first section.

FIELD OF THE INVENTION

The present disclosure relates to methods for producing oil and/or gas.

BACKGROUND OF THE INVENTION

Enhanced Oil Recovery (EOR) may be used to increase oil recovery infields worldwide. There are three main types of EOR, thermal,chemical/polymer and gas injection, which may be used to increase oilrecovery from a reservoir, beyond what can be achieved by conventionalmeans—possibly extending the life of a field and boosting the oilrecovery factor.

Thermal enhanced recovery works by adding heat to the reservoir. Themost widely practiced form is a steam-drive, which reduces oil viscosityso that it can flow to the producing wells. Chemical flooding increasesrecovery by reducing the capillary forces that trap residual oil.Polymer flooding improves the sweep efficiency of injected water.Miscible injection works in a similar way to chemical flooding. Byinjecting a fluid that is miscible with the oil, trapped residual oilcan be recovered.

Referring to FIG. 1 a, there is illustrated prior art system 100. System100 includes underground formation 102, underground formation 104,underground formation 106, and underground formation 108. Productionfacility 110 is provided at the surface. Well 112 traverses formations102 and 104, and has a horizontal portion with openings in formation106. The portion of formation 106 is shown at 114. Oil and gas areproduced from formation 106 through well 112, to production facility110. Gas and liquid may be separated from each other, gas is stored ingas storage 116 or further processed and/or transported and liquid isstored in liquid storage 118 or further processed and/or transported.

Well 132 traverses formations 102 and 104, and has a horizontal portionwith openings in formation 106 or well may have openings in multipleformations. The portion of formation 106 is shown at 134. Steam isinjected into well 132 from steam production facility 130, and thenflows across formation 106 to aid in the production of oil and/or gas towell 112.

Well 112 has a heel section where the horizontal portion of the wellintersects the vertical portion of the well, and a toe section at adistal end of the horizontal portion. These portions may be connected bya deviated section, such as a curve.

Well 132 has a heel section where the horizontal portion of the wellintersects the vertical portion of the well, and a toe section at adistal end of the horizontal portion.

As shown in FIG. 1 a, the toe section of a well 132 is aligned with theheel section of well 112, and the toe section of a well 112 is alignedwith the heel section of well 132.

Referring to FIG. 1 b, there is illustrated prior art system 100. System100 includes underground formation 102, underground formation 104,underground formation 106, and underground formation 108. Productionfacility 110 is provided at the surface. Well 112 traverses formations102 and 104, and has a horizontal portion with openings in formation 106or well may have openings in multiple formations. The portion offormation 106 is shown at 114. Oil and gas are produced from formation106 through well 112, to production facility 110. Gas and liquid may beseparated from each other, gas is stored in gas storage 116 or furtherprocessed and/or transported and liquid is stored in liquid storage 118or further processed and/or transported.

Well 132 traverses formations 102 and 104, and has a horizontal portionwith openings in formation 106. The portion of formation 106 is shown at134. Steam is injected into well 132 from steam production facility 130,and then flows across formation 106 to aid in the production of oiland/or gas to well 112.

Well 112 has a heel section where the horizontal portion of the wellintersects the vertical portion of the well, and a toe section at adistal end of the horizontal portion. These portions may be connected bya deviated section, such as a curve.

Well 132 has a heel section where the horizontal portion of the wellintersects the vertical portion of the well, and a toe section at adistal end of the horizontal portion.

As shown in FIG. 1 b, the toe section of a well 132 is aligned with thetoe section of well 112, and the heel section of a well 112 is alignedwith the heel section of well 132.

U.S. Pat. No. 5,215,146 discloses a method for reducing the time duringwhich steam moves in a lateral direction between two parallelsuperimposed horizontal wells when utilizing a Steam Assisted GravityDrainage (SAGD) process. Foam is added while injecting steam into anupper horizontal well once steam breakthrough occurs in an interwellregion. Foam enters the interwell region thereby causing an increasedpressure gradient. This increased pressure gradient adds to the gravityforce thereby providing a greater interstitial oil velocity whichincreases oil drainage between wells during startup. U.S. Pat. No.5,215,146 is herein incorporated by reference in its entirety.

Canadian Patent Number 2,277,378 discloses a pair of vertically spaced,parallel, co-extensive, horizontal injection and production wells and alaterally spaced, horizontal offset well are provided in a subterraneanreservoir containing heavy oil. Fluid communication is establishedacross the span of formation extending between the pair of wells.Steam-assisted gravity drainage (“SAGD”) is then practiced by injectingsteam through the injection well and producing heated oil and steamcondensate through the production well, which is operated under steamtrap control. Cyclic steam stimulation is practised at the offset well.The steam chamber developed at the offset well tends to grow toward thesteam chamber of the SAGD pair, thereby accelerating development ofcommunication between the SAGD pair and the offset well. This process iscontinued until fluid communication is established between the injectionwell and the offset well. The offset well is then converted to producingheated oil and steam condensate under steam trap control as steamcontinues to be injected through the injection well. The process yieldsimproved oil recovery rates with improved steam consumption. CanadianPatent Number 2,277,378 is herein incorporated by reference in itsentirety.

U.S. Patent Publication Number 2005/0082067 discloses that steamassisted gravity drainage (“SAGD”) is practiced in a first section of areservoir containing heavy oil. When steam/oil ratio rises sufficiently,steam injection into the first section is curtailed or terminated.Non-condensible gas is then injected into the section to pressurize itand production of residual oil and steam condensate is continued.Concurrently with pressurization, SAGD is practiced in an adjacentreservoir section. As a result, some of the residual oil in the firstsection is recovered and steam loss from the second section to the firstsection is ameliorated. U.S. Patent Publication Number 2005/0082067 isherein incorporated by reference in its entirety.

There is a need in the art for improved systems and methods for enhancedoil recovery. There is a further need in the art for improved systemsand methods for enhanced oil recovery using steam, for example throughviscosity reduction. There is a further need in the art for improvedsystems and methods for steam flooding. There is a further need in theart for improved systems and methods for enhanced oil recovery withsteam assisted gravity drainage (SAGD).

SUMMARY OF THE INVENTION

In one aspect, the invention provides a method for producing oil from anunderground formation comprising providing a first well in theformation, the first well comprising a plurality of sections along alength of the well; providing a second well in the formation; injectingan enhanced oil recovery formulation into at least a first section and asecond section of the first well and into the formation; forcing theformulation and/or oil towards the second well in the formation;producing the formulation and/or oil from the second well; and thenstopping the injecting into the second section, while continuing theinjecting into the first section.

Advantages of the invention include one or more of the following:

Improved systems and methods for enhanced recovery of hydrocarbons froma formation with steam.

Improved systems and methods for enhanced recovery of hydrocarbons froma formation with steam injected into a horizontal well.

Improved compositions and/or techniques for secondary recovery ofhydrocarbons.

Improved systems and methods for enhanced oil recovery.

Improved systems and methods for enhanced oil recovery using a SAGDprocess.

Improved systems and methods for enhanced oil recovery using gravitydrainage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a and 1 b illustrate an oil and/or gas production system.

FIG. 2 a illustrates an oil and/or gas production system.

FIG. 2 b illustrates an injection well of an oil and/or gas productionsystem.

FIG. 2 c illustrates a production well of an oil and/or gas productionsystem.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2 a:

Referring to FIG. 2 a, there is illustrated oil and/or gas productionsystem 200. System 200 includes underground formation 202, undergroundformation 204, underground formation 206, and underground formation 208.Production facility 210 is provided at the surface. Well 212 traversesformations 202 and 204, and has a horizontal portion with openings in abottom portion 214 of formation 206. Oil and gas are produced frombottom portion 214 of formation 206 through well 212, to productionfacility 210. Gas and liquid are separated from each other, gas isstored in gas storage 216 or further processed and/or transported andliquid is stored in liquid storage 218 or further processed and/ortransported.

Well 232 traverses formations 202 and 204, and has a horizontal portionwith openings in a top portion 234 of formation 206. Steam is injectedinto well 232 from steam production facility 230, and then flows acrossformation 206 to aid in the production of oil and/or gas to well 212.

In some embodiments, wells 212 and 232 may be used in a single formationor in multiple formations or portions of formations. For example, well232 may traverse formation 202, and have a horizontal portion withopenings in portion of formation 204 and/or portions of formation 206.Steam is injected into well 232 from steam production facility 230, andthen flows across formations 204 and 206 to aid in the production of oiland/or gas to well 212 in formation 206.

Well 212 has a heel section where the horizontal portion of the wellintersects the vertical portion of the well, and a toe section at adistal end of the horizontal portion, these portions may be connected bya deviated section such as a curve.

Well 232 has a heel section where the horizontal portion of the wellintersects the vertical portion of the well, and a toe section at adistal end of the horizontal portion, these portions may be connected bya deviated section such as a curve.

As shown in FIG. 2 a, the toe section of a well 232 is aligned with theheel section of well 212, and the toe section of a well 212 is alignedwith the heel section of well 232. In another embodiment, the toesection of a well 232 is aligned with the toe section of well 212, andthe heel section of a well 212 is aligned with the heel section of well232. The relative alignment of the toe sections and the heel sections isnot critical.

In some embodiments, the vertical spacing between the horizontal sectionof well 212 and the horizontal section of well 232 may be from about 5to about 150 meters, for example from about 10 to about 50 m.

In some embodiments, the horizontal spacing between the horizontalsection of well 212 and the horizontal section of well 232 may be fromabout 5 to about 200 meters, for example from about 10 to about 100 m.

In some embodiments, the horizontal section of well 212 may have alength from about 50 to about 2000 m, for example from about 200 toabout 1000 m.

In some embodiments, the horizontal section of well 232 may have alength from about 50 to about 2000 m, for example from about 200 toabout 1000 m.

In some embodiments, formation 206 may be at a depth from about 50 toabout 5000 m, for example from about 100 to 500 meters deep.

In some embodiments, wells 212 and 232 may be horizontal and may be usedfor a SAGD type recovery, where steam is injected into well 232 whichforms a steam chamber above and around well 232. The steam mobilizes oilin the area which drains by gravity to well 212.

In some embodiments, wells 212 and 232 may be horizontal and may be usedfor a steam drive type recovery, where steam is injected into well 232which mobilizes oil in the area and forces the oil towards well 212. Insome embodiments, wells 212 and/or wells 232 may be vertical wells.

In some embodiments, wells 212 and 232 may be horizontal and may be usedfor a hybrid SAGD and steam drive type recovery.

In some embodiments, wells 212 and 232 may be used for an EOR recovery,for example where steam, water, solvents, polymers, surfactants, akalis,and/or mixtures thereof may be injected into well 232 to produce moreoil from well 212. In some embodiments, wells 212 and/or wells 232 maybe vertical wells.

Although wells 212 and 232 are shown with an abrupt right angletransition from vertical to horizontal, in some embodiments, wells 212and 232 may have a smooth transition from vertical to deviated tohorizontal, for example with a smooth curved radius.

FIG. 2 b:

Referring now to FIG. 2 b, a detailed view of the horizontal section ofwell 232 is shown. The horizontal section of well 232 includes section232 a, section 232 b, and section 232 c. Steam supply line 240 isconnected to the steam source 230 at a first end, and is located withinthe vertical section well 232, and then is connected to valves 242 a,242 b, and 242 c at a second end. Section 232 a, section 232 b, andsection 232 c are separated from each other by dividers 270. Suitabledividers 270 include packers, cup seals, steam diverters, or a wallacross well 232.

Section 232 a includes valve 242 a which diverts a portion of steam fromsteam supply line 240 into chamber 244 a. Steam exits the chamber 244 athrough perforations 246 a and flows into formation portions 234. One ormore sensors 248 a are provided adjacent to perforations 246 a tomeasure formation and/or oil properties, such as pressure, temperature,chemical properties, etc. Sensors 248 a could be a pressure transducer,a thermometer, a thermocouple, a fiber optic sensor, or other sensors asare known in the art.

Section 232 b includes valve 242 b which diverts a portion of steam fromsteam supply line 240 into chamber 244 b. Steam exits the chamber 244 bthrough perforations 246 b and flows into formation portions 234. One ormore sensors 248 b are provided adjacent to perforations 246 b tomeasure formation and/or oil properties, such as pressure, temperature,chemical properties, etc. Sensors 248 b could be a pressure transducer,a thermometer, a thermocouple, a fiber optic sensor, or other sensors asare known in the art.

Section 232 c includes valve 242 c which diverts a portion of steam fromsteam supply line 240 into chamber 244 c. Steam exits the chamber 244 cthrough perforations 246 c and flows into formation portions 234. One ormore sensors 248 c are provided adjacent to perforations 246 c tomeasure formation and/or oil properties, such as pressure, temperature,chemical properties, etc. Sensors 248 c could be a pressure transducer,a thermometer, a thermocouple, a fiber optic sensor, or other sensors asare known in the art.

Although perforations 246 a, 246 b, and 246 c may be used, in otherembodiments, other types of openings may be used, for example, a slottedliner, a sand screen, a wire-wrap screen, a casing, a liner, or othercompletion methods as are known in the art giving connection betweenwellbore and formation.

Although section 232 a, section 232 b, and section 232 c are shown ashorizontal sections in the Figure, in some embodiments, section 232 a,section 232 b, and section 232 c may be a horizontal section, a verticalsection, or a deviated section for example from about 15 to about 75degrees from horizontal.

FIG. 2 c:

Referring now to FIG. 2 c, a detailed view of the horizontal section ofwell 212 is shown. The horizontal section of well 212 includes section212 a, section 212 b, and section 212 c. Oil and/or gas production line250 is connected to the production facility 210 at a first end, and islocated within the vertical section of well 212, and then is connectedto valves 252 a, 252 b, and 252 c at a second end. Section 212 a,section 212 b, and section 212 c are separated from each other bydividers 272. Suitable dividers 272 include packers, cup seals, steamdiverters, or a wall across well 212.

Section 212 a includes valve 252 a which allows oil and/or gas and/orsteam or other injected fluids in chamber 254 a to flow into valve 252 aand then into oil and/or gas production line 250. Oil and/or gas flowinto the chamber 254 a through perforations 256 a from formationportions 214. One or more sensors 258 a are provided adjacent toperforations 256 a to measure formation and/or oil properties, such aspressure, temperature, chemical properties, etc. Sensors 258 a could bea pressure transducer, a thermometer, a thermocouple, a fiber opticsensor, or other sensors as are known in the art.

Section 212 b includes valve 252 b which allows oil and/or gas and/orsteam or other injected fluids in chamber 254 b to flow into valve 252 band then into oil and/or gas production line 250. Oil and/or gas flowinto the chamber 254 b through perforations 256 b from formationportions 214. One or more sensors 258 b are provided adjacent toperforations 256 b to measure formation and/or oil properties, such aspressure, temperature, chemical properties, etc. Sensors 258 b could bea pressure transducer, a thermometer, a thermocouple, a fiber opticsensor, or other sensors as are known in the art.

Section 212 c includes valve 252 c which allows oil and/or gas and/orsteam or other injected fluids in chamber 254 c to flow into valve 252 cand then into oil and/or gas production line 250. Oil and/or gas flowinto the chamber 254 c through perforations 256 c from formationportions 214. One or more sensors 258 c are provided adjacent toperforations 256 c to measure formation and/or oil properties, such aspressure, temperature, chemical properties, etc. Sensors 258 c could bea pressure transducer, a thermometer, a thermocouple, a fiber opticsensor, or other sensors as are known in the art.

Although section 212 a, section 212 b, and section 212 c are shown ashorizontal sections in the Figure, in some embodiments, section 212 a,section 212 b, and section 212 c may be a horizontal section, a verticalsection, or a deviated section for example from about 15 to about 75degrees from horizontal.

Although perforations 256 a, 256 b, and 256 c may be used, in otherembodiments, other types of openings may be used, for example, a slottedliner, a sand screen, a wire-wrap screen, a casing, a liner, or othercompletion methods as are known in the art giving connection betweenwellbore and formation.

Operation:

In operation, steam may be generated at steam source 230 and then pumpedthrough steam supply line 240 to valves 242 a, 242 b, and 242 c. Aportion of steam will be supplied to each of the chambers 244 a, 244 b,and 244 c. Steam will then flow into the formation portions 234, thatwill act to heat, mobilize, lower the viscosity of, and/or force oiland/or gas across the formation 206 and into the formation portions 214.Oil and/or gas will then enter into the chambers 254 a, 254 b, and 254 cthrough the perforations 256. The oil and/or gas will be collected inthe oil production line 250 and brought to the surface.

If the formation 206 between section 232 a and section 212 a has ahigher porosity and/or many more fractures than the portion of theformation between section 232 c and section 212 c, then much more steamwill flow between section 232 a and section 212 a. This high volume ofsteam pumped across the formation 206 between section 232 a and section212 a will cause that section of the formation to get much hotter thanthe portion of the formation between section 232 c and section 212 c. Itcould also cause an increased volume of oil and/or gas across thatsection of the formation 206. In such a case, the valve 242 a could beturned off for a period of time, or turned down for period of time sothat less steam would be provided to section 232 a.

It is generally desirable in a steam flooding operation to uniformlyheat the formation adjacent to all of the sections 232 a, 232 b, and 232c; and/or to uniformly produce oil and/or gas across the formation 206adjacent to all of the sections 232 a, 232 b, and 232 c. In order toachieve the goals of uniformly heating the formation and/or uniformlyproducing oil and/or gas, valves 242 a, 242 b, and 242 c may be used toprovide more steam to sections that are cooler and less steam tosections that are hotter. In addition, valves 252 a, 252 b, and 252 cmay be used to reduce the flow of oil and/or gas and/or steam or otherinjected fluids from fast flowing sections, and to increase the flow ofoil and/or gas and/or steam or other injected fluids from slow flowingsections.

In some embodiments, valves 242 a, 242 b, and 242 c are on-off valves,while in other embodiments valves 242 a, 242 b, and 242 c may bepositioned on, off, and numerous positions in between which arepartially on.

In some embodiments, valves 252 a, 252 b, and 252 c are on-off valves,while in other embodiments valves 252 a, 252 b, and 252 c may bepositioned on, off, and numerous positions in between which arepartially on.

In some embodiments, valves 242 a, 242 b, and 242 c and valves 252 a,252 b, and 252 c may be controlled from the surface, for examplehydraulically controlled, electrically controlled, and/or mechanicallycontrolled.

In some embodiments, valves 242 a, 242 b, and 242 c may be used in well232 with no valves in well 212.

In some embodiments, valves 252 a, 252 b, and 252 c may be used in well212 with no valves in well 232.

In some embodiments, valves 242 a, 242 b, and 242 c may be used in well232 and valves 252 a, 252 b, and 252 c may be used in well 212.

In some embodiments, suitable control valves 252 and 242 arecommercially available from e.g., Baker Hughes, Halliburton, andSchlumberger.

The recovery of oil and/or gas with array of wells 200 from anunderground formation may be accomplished by any known method. Suitablemethods include subsea production, surface production, primary,secondary, or tertiary production. The selection of the method used torecover the oil and/or gas from the underground formation is notcritical.

Although above the steam has been discussed as the injectant, otherinjectants can also be used with the system to increase the flow of oilfrom the formation. In some embodiments, oil and/or gas may be recoveredfrom a formation into a well, and flow through the well and flowline toa facility. In some embodiments, enhanced oil recovery, with the use ofan agent for example steam, water, a surfactant, a polymer flood, and/ora miscible agent such as a solvent and/or a gas such as carbon dioxide,may be used to increase the flow of oil and/or gas from the formation.In some embodiments, suitable miscible enhanced oil recovery agentsinclude carbon disulfide, hydrogen sulfide, carbon dioxide, octane,pentane, LPG, C2-C6 aliphatic hydrocarbons, nitrogen, diesel, mineralspirits, napthsteam, asphalt solvent, kerosene, acetone, xylene,trichloroethane, or mixtures of two or more of the preceding, or othermiscible enhanced oil recovery agents as are known in the art. In someembodiments, suitable miscible enhanced oil recovery agents are firstcontact miscible or multiple contact miscible with oil in the formation.In some embodiments, suitable immiscible enhanced oil recovery agentsinclude water in gas or liquid form, air, mixtures of two or more of thepreceding, or other immiscible enhanced oil recovery agents as are knownin the art. In some embodiments, suitable immiscible enhanced oilrecovery agents are not first contact miscible or multiple contactmiscible with oil in the formation.

In some embodiments, immiscible and/or miscible enhanced oil recoveryagents injected into the formation may be recovered from the producedoil and/or gas and re-injected into the formation.

In some embodiments, oil as present in the formation prior to theinjection of any enhanced oil recovery agents has a viscosity of atleast about 100 centipoise, or at least about 500 centipoise, or atleast about 1000 centipoise, or at least about 2000 centipoise, or atleast about 5000 centipoise, or at least about 10,000 centipoise. Insome embodiments, oil as present in the formation prior to the injectionof any enhanced oil recovery agents has a viscosity of up to about5,000,000 centipoise, or up to about 2,000,000 centipoise, or up toabout 1,000,000 centipoise, or up to about 500,000 centipoise.

Releasing at least a portion of the enhanced oil recovery agent and/orother liquids and/or gases may be accomplished by any known method. Onesuitable method is injecting steam into a single conduit in a singlewell, allowing the steam to soak, and then pumping out at least aportion of the steam with gas and/or liquids. Another suitable method isinjecting the steam into a first well, and pumping out at least aportion of the steam with gas and/or liquids through a second well. Theselection of the method used to inject at least a portion of the steamand/or other liquids and/or gases is not critical.

In some embodiments, the steam and/or other liquids and/or gases may bepumped into a formation at a pressure up to the fracture pressure of theformation.

In some embodiments, water may be heated prior to being injected intothe formation to lower the viscosity of fluids in the formation, forexample heavy oils, paraffins, asphaltenes, etc.

In some embodiments, water may be heated and/or boiled while within theformation, with the use of a heated fluid or a heater, to lower theviscosity of fluids in the formation. In some embodiments, water may beheated and/or boiled while within the formation, with the use of aheater. One suitable heater is disclosed in copending United StatesPatent Application having Ser. No. 10/693,816, filed on Oct. 24, 2003,and having attorney docket number TH2557. United States PatentApplication having Ser. No. 10/693,816 is herein incorporated byreference in its entirety.

In some embodiments, steam may be pumped into a formation below thefracture pressure of the formation, for example from about 40% to about90% of the fracture pressure.

In some embodiments, a quantity of steam or steam mixed with othercomponents may be injected into a well, followed by another component toforce steam or steam mixed with other components across the formation,for example air; water in gas or liquid form; water mixed with one ormore salts, polymers, and/or surfactants; carbon dioxide; other gases;other liquids; and/or mixtures thereof.

Illustrative Embodiments

In one embodiment, there is disclosed a method for producing oil from anunderground formation comprising providing a first well in theformation, the first well comprising a plurality of sections along alength of the well; providing a second well in the formation; injectingan enhanced oil recovery formulation into at least a first section and asecond section of the first well and into the formation; forcing theformulation and/or oil towards the second well in the formation;producing the formulation and/or oil from the second well; and thenstopping the injecting into the second section, while continuing theinjecting into the first section.

In some embodiments, the first well further comprises a first array ofwells, and the second well further comprises a second array of wells,wherein a well in the first array of wells is at a distance of 5 metersto 100 meters from one or more adjacent wells in the second array ofwells. In some embodiments, the first well comprises from about 3 toabout 20 sections along the length of the first well. In someembodiments, the enhanced oil recovery formulation comprises steam. Insome embodiments, stopping the injecting into the second sectioncomprises turning off a valve in the second section. In someembodiments, the second well comprises a plurality of sections along alength of the well. In some embodiments, the first well comprises anarray of wells of 5 to 500 wells, and the second well comprises an arrayof wells of 5 to 500 wells. In some embodiments, producing theformulation and/or oil mixture from the second well comprises producingfrom a first section and from a second section of the second well; andthen stopping the production into the second section, while continuingthe production into the first section. In some embodiments, theunderground formation comprises an oil having a viscosity from 100 to5,000,000 centipoise. In some embodiments, the method also includesconverting at least a portion of the recovered oil into a materialselected from the group consisting of transportation fuels such asgasoline and diesel, heating fuel, lubricants, chemicals, and/orpolymers. In some embodiments, the steam is injected at a pressure from0 to 37,000 kilopascals above the initial reservoir pressure, measuredprior to when the injection begins. In some embodiments, the undergroundformation comprises a permeability from 0.0001 to 15 Darcies, forexample a permeability from 0.001 to 1 Darcy. In some embodiments, anyoil, as present in the underground formation prior to the injecting theformulation, has a viscosity from 5000 to 2,000,000 centipoise, forexample from 10,000 to 500,000 centipoise. In some embodiments, themethod also includes sensing at least one of a pressure and atemperature at the first section and the second section of the firstwell. In some embodiments, the method also includes sensing at least oneof a pressure and a temperature at a first section and a second sectionof the second well.

Those of skill in the art will appreciate that many modifications andvariations are possible in terms of the disclosed embodiments of theinvention, configurations, materials and methods without departing fromtheir spirit and scope. Accordingly, the scope of the claims appendedhereafter and their functional equivalents should not be limited byparticular embodiments described and illustrated herein, as these aremerely exemplary in nature.

1. A method for producing oil from an underground formation comprising:providing a first well in the formation, the first well comprising aplurality of sections along a length of the well; providing a secondwell in the formation; injecting an enhanced oil recovery formulationinto at least a first section and a second section of the first well andinto the formation; producing the formulation and/or oil from the secondwell; and then modifying the injecting into the second section, whilecontinuing the injecting into the first section.
 2. The method of claim1, wherein the first well further comprises a first array of wells, andthe second well further comprises a second array of wells, wherein awell in the first array of wells is at a distance of 5 meters to 200meters from one or more adjacent wells in the second array of wells. 3.The method of claim 1, wherein the first well comprises from about 3 toabout 20 sections along the length of the first well.
 4. The method ofclaim 1, wherein the enhanced oil recovery formulation comprises steam.5. The method of claim 1, wherein modifying the injecting into thesecond section comprises actuating a valve in the second section.
 6. Themethod of claim 1, wherein the second well comprises a plurality ofsections along a length of the well.
 7. The method of claim 1, whereinthe first well comprises an array of wells of 5 to 500 wells, and thesecond well comprises an array of wells of 5 to 500 wells.
 8. The methodof claim 6, wherein producing the formulation and/or oil mixture fromthe second well comprises producing from a first section and from asecond section of the second well; and then modifying the productioninto the second section, while continuing the production into the firstsection.
 9. The method of claim 1, wherein the underground formationcomprises an oil having a viscosity from 100 to 5,000,000 centipoise.10. The method of claim 9, further comprising converting at least aportion of the recovered oil into a material selected from the groupconsisting of transportation fuels such as gasoline and diesel, heatingfuel, lubricants, chemicals, and/or polymers.
 11. The method of claim 4,wherein the steam is injected at a pressure from 0 to 37,000 kilopascalsabove the initial reservoir pressure, measured prior to when theinjection begins.
 12. The method of claim 1, wherein the undergroundformation comprises a permeability from 0.0001 to 15 Darcies.
 13. Themethod of claim 1, wherein any oil, as present in the undergroundformation prior to the injecting the formulation, has a viscosity from5000 to 2,000,000 centipoise.
 14. The method of claim 1, furthercomprising sensing at least one of a pressure and a temperature at thefirst section and the second section of the first well.
 15. The methodof claim 1, further comprising sensing at least one of a pressure and atemperature at a first section and a second section of the second well.16. The method of claim 1, wherein the second well comprises a pluralityof sections along a length of the well; further comprising modifying theproduction into a first plurality of sections of the second well, whilecontinuing the production into a second plurality of sections of thesecond well.
 17. The method of claim 1, further comprising modifying theinjecting into a first plurality of sections of the first well, whilecontinuing the injecting into a second plurality of sections of thefirst well.